A Surface-conduction Electron-emitter Display (SED) is a flat panel display technology that uses surface conduction electron emitters for every individual display pixel. The surface conduction electron emitter emits electrons, that excite a phosphor coating on the display panel which is similar to the basic concept found in traditional cathode ray tube (CRT) televisions. This means that SEDs can combine the slim form factor of LCDs with the high contrast ratios and can also refresh rates making the picture quality of CRTs better .The researches so far claim that the SED consumes less power than the LCD displays. The surface conduction electron emitter apparatus consists of a thin slit, across which electrons tunnel when excited by moderate voltages (tens of volts).
When the electrons cross electric poles across the thin slit, some are scattered at the receiving pole and are accelerated towards the display surface by a large voltage gradient (tens of kV) between the display panel and the surface conduction electron emitter apparatus. The SED display offer brightness, color performance and viewing angles on par with CRTs. However, they do not require a deflection system for the electron beam. Engineers as a result can create a display that is just a few inches thick which is still light enough for wall-hanging designs. The manufacturer can enlarge the panel merely by increasing the number of electron emitters relative to the necessary number of pixels. Since 1987, SED technology has been developing. Canon and Toshiba are the two major companies working on SEDs